1. Field of the invention
The present invention relates to a hard film-coated member coated with a hard film on the surface thereof, and a jig for molding using the member.
2. Description of the Related Art
Conventionally, jigs for metal working such as dies have been improved in wear resistance and seizure resistance by a nitriding treatment. Further, in recent years, a study has been conducted on the improvement of the wear resistance and the seizure resistance by gas phase coating such as PVD in place of a nitriding treatment. For example, JP-A No. 2000-144376 discloses a hard film improved in wear resistance by the formation of a composite nitride containing two or more of Cr, Al, Ti, and V. Whereas, JP-A No. 2002-307128 and JP-A No. 2002-307129 disclose a coated jig for warm working excellent in wear resistance or seizure resistance, including a coated layer formed of one or more nitrides, carbides, and carbonitrides of Ti, V, Al, Cr, and Si formed therein, and, optionally, a sulfide layer including Ti and Cr, and the balance of Mo further formed thereon. Further, JP-A No. 2000-1768 discloses a hard film excellent in wear resistance and seizure resistance, including a surface layer containing MoS2 as a main component on a high hardness film; and an article with the film. Further, JP-A No. 2006-124818 discloses a hard film including (Xc, M1-c)(BaCbN1-a-b), where M is one or more of W and V, and X is one or more of elements of Groups 4A and 5A, Al, Si, Fe, Co, and Ni; and a formation method thereof.
However, the hard film including a composite nitride containing two or more of Cr, Al, Ti, and V described in JP-A No. 2000-144376 has high hardness, and is excellent in wear resistance, but is insufficient in seizure resistance. Thus, when plastic working of a metal is carried out under a high surface pressure, or in other cases, the hard film cannot withstand use in a severe environment. Whereas, the coated layer including one or more nitrides, carbides, and carbonitrides of Ti, V, Al, Cr, and Si disclosed in JP-A No. 2002-307129 also similarly has high hardness, but is inferior in seizure resistance.
Then, when the sulfide layer is formed as described in JP-A No. 2002-307128 or JP-A No. 2000-1768, the sulfide is soft, and it is excellent in sliding property (wear resistance) at the beginning of use, but wears with time in use. Thus, the wear resistance cannot be kept over a long period. Whereas, also for the hard film including (Xc, M1-c)(BaCbN1-a-b) described in JP-A No. 2006-124818, as with the case of the sulfide layer, the sliding property (wear resistance) is excellent at the beginning of use, but the wear resistance cannot be kept over a long period.
Further, when the coated layer including nitride, carbide, and carbonitride selected from one or more of Ti, V, Al, Cr, and Si of JP-A No. 2002-307128 or JP-A No. 2002-307129 is directly formed on a low-hardness iron type base material, unfavorably, peeling tends to occur (adhesion decreases) due to a difference in elasticity and plastic deformation behavior from the base material.